Concept on positioning of Columns

1).

Investigation of framing plan w r t symmetry in X direction

• If we split the plan vertically half, it will look mirrored. So we conclude the given plan is symmetric in X direction

Investigation of the framing plan w r t symmetry in Y Direction.

• If we split plan horizontally half it will look mirrored. So we conclude the given plan is symmetric in Y-direction

Investigation of the framing plan w r t redundancy in X direction

• The column in X direction are comparatively more and evenly spaced. So the Structure is more redundant in X direction. Except the top and bottom column rows are having quite longer spans

Investigation of the framing plan w r t redundancy in Y direction

• The column in y direction are comparatively lesser but evently spaced. So the Structure is redundant but lesser than that of x direction 

Investigation w r t Bi-directional stiffness

• The column in horizontal Direction are connected with straight to staight beams. This means any lateral load passing from left end of the building will have it's path straight till it reaches right end of the building. So no or less possibility of force diversion takes place
• The column in vertical direction are not connected with straight to staight beams. So lateral load passing from south side of building will get diverted to east and west direction to reach next day . There will be major force diversion takes place with sesmic force in y direction. The framing plan is weak w r t to Bi-directional stiffness in y direction

Investigation of the framing plan w r t ductility

• Prima facie, the aspects ratio of plan clearly hints more column in X direction compared to y direction. It will result in higher stiffness of the building in X direction, which would reduce ductility in X axis
• Moreover, the x -force will easily pass from one Bay to it's next due to beam alignment. Whereas, the y force will struggle to pass through. The north- South beam are arranged in zig zag Which leads to discontinue bracing. We can conclude that the given framing plan is more ductile in y direction than that in X direction

2).

The building plan area is large in bottom stories.

      The floor plan areas are getting reduced with increase in height. These building offset has to crosschecked with reference to IS 1893-2016 Table-6 serial number (iii)

Soft storey

      The building has uncovered opening in sixth floor. As there is no occupancy or a partition wall this will lead to plastic hinge formation at column with reference to IS 1893-2016 fig 4A). This has to be checked and sufficient designed

Slopy base

     The building is constructed on sloping ground at one side. This will lead to significant variation in the stiffness with reference to IS 1893-2016 fig 5E .Few levels May be subjected to soft storey mechanism

3).

Open ground floor 

• This denote soft storey mechanism acting in the building 

Rooms along 2 bays seperated by an open corridors 

• The bays field with room will have higher mass compared to middle bay left open for corridors. This induce mass irregularities along height uniformly 

Two short side covered with infill walls

• This means building left and right  side periphery is more stiffer during sesmic force (especially along north south)

Staircase portion at left top corner 

• Usually staircase and lift portion are stiffer than other part because of concentrated concrete elements. So the staircase portion contains more stiffness in provided building plan 

No framing connection in Y-direction  

• We could see no structural beam provided along the vertical direction between columns. This makes the building more vulnerable during North south sesmic force 

Beams connected along column minor axis 

• The column are having longer dimension in y direction. This means they are more stiffer along y direction. But the beams are running only in x direction which would attract much lesser lateral forces and hardly transfers it

Variation in column size 

• The internal column are having higher sizes compared to exterior column. But this will lead to significant differences in lateral drift of column. So the concrete floor might have suffered heavy out of plane shear which would led to collapse